Elastic fluid turbine



Jan. 6, 1942. 4D. J. BLooMBL-:RG

ELASTIC FLUID r'.l/URBIIUI Filed Deo. 8, 1939 I STTOP: David .Bloombe His Attori-r1 ey.

`Patented Jan. 6, 1942 Davia J. Bloomberg, yitewtn,v Massgassignor tu General Electricv Company,- a lcorporationo I New 'York y Application December s, 19,39, serial No. 08,158

misti-ms.y (criss-L69) f l .f

Thefpresent invention relates to elastic fluid turbines, particularly of the type which` include a lfirst stage with a bucket wheel having at least two axially spaced rows of buckets although it is not necessarily limited thereto. In certain cases, such as where turbines are used for ship propuln sion, 'they are subject to considerable speed Variation. In such cases two essentially different op-v erating conditions may occur, one condition at cruising speeds with a large first stage pressure ratio and low wheel speed and the other condition with a low first stage pressure ratio and a high wheel speed. From a design standpoint, the first condition can best be satisfied by a first stage bucket wheel having at leasttwo axially spaced rows of buckets, whereas the second condition-calls for a single row wheel. .s f

,The object of my invention isto provide an improved construction and arrangement of elastic fluid turbines subject to both conditions aforementioned which may be efficiently and economically operated. 'Ihis is accomplished in accordance with my invention by the provision ofk a bucket wheel or wheels having several rows of buckets and a device for by-passing elastic fluid discharged from a section 'of the first row with regard to the other row or rows of buckets. The elastic fluid bypassedl with regard to the other rows of buckets is conducted directly to a lower stage. With such an arrangement more than 10% improvement in cruising economy, that is during low speed operation, may be attained'at a sacrifice of only 1% of maximum speed economy.

For a better understanding of what I' believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 is a sectional View of an elastic fluid turbineL embodying my invention; Fig. 2 is a section along lines 2-2 of Fig. 1; and Fig. 3 is a section along lines 3-3 of Fig. 1.

The turbine arrangement comprises an outer casing I including a solid rotor forming a shaft with a first stage bucket wheel I2 and a second stage bucket wheel I3. Elastic fluid is'conducted to the turbine through a valve Chest I4 forming chambers I5, I6 and I1 communicating with separate sections of a rst stage nozzle plate I8 supported on the casing I0. `The flow to the chambers I5, I6, I1 is controlled by valve means I9. During low or cruising speed operation the valve I9 for the chamber l5 is opened while the vice versa, during high speed koperation the valve I9 for chamber I5 is closed and the valves I9 for chambers IB and are opened.

s The first bucket wheel I2 has -two complete rows of buckets 20 and 2|. According to my invention I-provide means whereby a portion of the elastic `fluid discharged from the y row of buckets 20 is conducted to the row of'buckets 2| and another portion of -the elastic -fluid discharged from the row-of buckets 2D is bypassed with-regard to the row of buckets 2| and conducted `directlyto a lower stage, in the'present instance the second stage, including the aforementioned wheel I3 andia nozzle diaphragm 22. To this end I provide an intermediate nozzle plate 23 ybetween the two rows of buckets 20, 2| in alinement with thatsection of theV first row of buckets 20 vwhich receives elastic fluid from the first chamber I5. intermediate nozzle' plate 23 vextends over arc of approximately 30?. The intermediate nozzle plate 23 is suitably supported on the outer casing III. Thus, the elastic fluid discharged from the chamber I5 of the valve chest first passes through the first row of buckets 20 and is then properly directed by the intermediate nozzle plate 23 to the second row of buckets to be discharged therefrom into the second stage.

The elastic fluid discharged from the valve chest chambers I6, I1 passes through the rvfirst row of buckets and thereafter is bypassed with regard to the second row of buckets 2|. 'This is accomplished by shielding and guiding devices 24 and 25, each extending over an arc Acorresponding to the arcs of supply from the chambers I6 and I1. Each device has an outer wall 26 secured to webs 21 by means of screws 28 and side walls 29 and 3l)r respectively located on opposite sides of the row of buckets 2|, both walls acting as shields to prevent passage of elastic fiuid through the row of buckets v2|. The side wall 29 which is located between the two rows of kbuckets 20, 2| is curved smoothly to deflect and 29 adjacent the row of 'buckets 20. The vanes 3| in the present instance are inclined ab0ut45 tothe direction of elastic uid discharged from the row of buckets 20.

During operation elastic fiuid is supplied from the chamber I5 and passed through thetwo rows of buckets 20 and 2| during cruising condition valves for chambers I6 and II are closed and, 55 and elastic fluid is supplied from the chambers In the present instance the v I6, l1 during high speed condition. The elastic uid supplied from the chambers I6 and I1 is passed through the rst row of buckets 20 and bypassed with regard to the second row of buckets 2|.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Elastic fluid turbine comprising a casing,

rst stage wheel means with at least two axially spaced rows of buckets, means for conducting elastic iiuid to the rst row of buckets, an intermediate nozzle plate for directing elastic fluid discharged from a section of the iirst row to a section of the second row, and a shielding and guiding device for bypassing elastic uid discharged from another section of the first row with regard to another section of the second row and to prevent the iow of uid through the other section of the second row, said device being supported on the casing and having a curved wall disposed between the two rows of-buckets, and another wall adjacent the outlet side of the other section of the second row.

2. Elastic fluid turbine comprising first stage wheel means with at least two axially spaced rows of buckets, means including a nozzle plate for conducting elastic fluid to the first row of buckets, an intermediate nozzle plate for directing elastic fluid discharged from a section `of the iirst row to a section of the second row, and a shielding and guiding device for bypassing elastic fluid discharged from another section of the first row with regard to another section of the second row and to prevent the flow of fluid through said other section of the second row, said device enclosing both sides of a section of the second row of buckets and having a curved wall between the two rows of buckets and a plurality of directing vanes secured to the curved wall adjacent the first row of buckets.

3. Elastic uid turbine comprising a casing, a

first stage nozzle plate, a valve chest forming separate chambers for conducting elastic fluid to two separate sections of the nozzle plate, first stage bucket wheel means having axially spaced first and second rows of buckets, the first row being arranged to receive elastic iiuid issued from both sections of the nozzle plate, an intermediate nozzle plate between the two rows of buckets for conducting a portion of elastic fluid issued :from one section of the rst row to the second row, and a device detachably supported on and spaced from the casing to define a channel therewith, the device having walls enclosing and shielding a section of the second row to prevent the flow of iiuid therethrough and to bypass fluid discharged from the first row with regard to the second row, one of said walls being curved and having guide vanes to form a smooth passage for the bypassed fluid.

4. Elastic fluid turbine comprising a casing, a bucket wheel located in the casing and having a iirst and a second row of buckets, means for conducting elastic iiuid tothe first row of buckets, nozzle means located between the two rows of buckets for conducting elastic fluid discharged from a section of the iirst row to a section of the second row, means for bypassing substantially all of the elastic fluid discharged from another section of the first row with regard to the second row, said means comprising a segmental channel member having walls on opposite sides of the second row and defining with the casing a bypass channel, one of said walls being located between the two rows of buckets and having guide vanes adjacent the first row of buckets to conduct fluid discharged from the other section of said first row into said bypass channel, and another bucket wheel arranged to receive uid conducted through the bypass.

DAVID J. BLOOMBEiRG. 

